1. Field of the Invention
The present invention is directed to a bearing for the rotating anode of an x-ray tube.
2. Description of the Prior Art
When rotatably supporting a rotating anode with the assistance of one or more rolling bearings, difficulties in long-term operation of the x-ray tube arise in conjunction with the intense and partly non-uniform heating of the bearing. As a consequence of the heating, the radial air of the rolling bearing changes substantially, so that a seizing of the bearing and thus an outage of the x-ray tube is possible in the extreme case. In order to avoid this, such extensive bearing play is selected in practice for the rolling bearing that a seizing of the bearing is reliably precluded. In certain operating conditions of the x-ray tube, however, this leads to increased wear, and thus a shorter useful life, and also results in a greater development of noise and to relatively great displacements of the focus of the x-ray tube during operating.
In an effort to solve this problem, it has been proposed that rolling bearings, suitable for absorbing axial forces, be loaded with an axially directed force for suppressing the bearing play in addition to being loaded with the bearing forces that already occur due to the bearing of the rotating anode. German OS 15 89 893 and German PS 726 051 teach merely using the influence of the force of gravity to produce this force. This approach, however, is only practical when the rotating anode shaft is vertically oriented. Other solutions usually involve considerable structural outlay that causes corresponding increased costs. In the x-ray tube disclosed in German AS 10 21 511, for example, special curved washers are required for producing the axial force.